Calculating recovery time of an application system

ABSTRACT

Mechanisms are provided for calculating a recovery time (t r ) of an application system in a computer system. The mechanisms tune the computer system dynamically. A recovery time (t r ) is calculated and controlled within flexible predefined time slices and compared to a predefined time period (t 0 ). A trigger is set in the case in which the calculated recovery time (t r ) exceeds the predefined time period (t 0 ). The mechanisms determine a type of redolog used during a backup process and a corresponding recovery speed value associated with the type of redolog. The recovery time is calculated based on the type of redolog used during the backup process and the corresponding recovery speed value associated with the type of redolog.

BACKGROUND

The invention relates in general to a method for calculating a recoverytime of an application system in a computer system for tuning thecomputer system dynamically so an agreed recovery time can be secured.

The invention further refers to an appropriate computing system, acomputer program and a computer program product.

The use of and dependency on data in today's society is rapidlyexpanding. Now more than ever, businesses continuously rely on data inorder to operate. Businesses and their customers demand that the data beavailable and accurate. Those data may originate from different areas.The main part of those data within a company are stored within aso-called database management system. Such a database management systemserves to store and manage large amounts of data.

Over time in a typical computer environment, large amounts of data aretypically written to and retrieved from storage devices connected to thecomputer. As more data are exchanged with the storage devices, itbecomes increasingly difficult for the data owner to reproduce thesedata if the storage devices fail. Internal influences can lead to abreakdown of data carrier or of processors. A software mistake, mostlybased on a bad design can also occur.

The consequences of data loss can be fatal for a business company,resulting in an economic damage. Therefore, regarding data storages, itis common practice to generate a copy of said data which can be restoredon demand.

So one of the most important aspects within a database management systemis the protection of one's organization's data from logical errors,disasters and other failures by storing backup and archive copies ofdata on offline storage. A so-called backup describes generally the stepof copying data within a computer system on a storage medium as well asthe copy itself. Doing a regular backup alone is no guaranteedprotection against data loss since there may be internal influences tothe backup system which make the backup invalid.

An execution of such a backup can result in utilisation of a largenumber of resources for a long period of time because of the largeamount of data to be stored. Nevertheless, it is very important toexecute backups regularly, for that several versions of backups areavailable in case of a restore. The so-called recovery of data providesthe database after restoring with complete functionality, so that alldata of the database are available without restrictions.

One way of protecting data is by backing up the data to backup media,e.g., tapes or disks. Such backup is typically performed manually orautomatically at preset intervals using backup software. The backupmedia are then stored away in a safe location. Various conventionalmechanisms for protecting and recovering data are available forbusinesses.

The so-called backup systems vary in the levels of protection theyprovide, the amount of time required to restore the backed up data andthe difficulty associated with their integration with the businesses'other systems and applications.

Generally, the success of these mechanisms is measured in terms of “dataavailability” i.e., how quickly a system, a database, or a file can berestored after a failure or corruption of data. In the following anysystem which can be an object of a backup and restoring process,respectively, will be subsumed under the term “application system”.

There are mainly two types of backup procedures and systems available.

One type of backup can be referred to as an “offline” backup. In anoffline backup, an application system that is being backed up has to bequiesced and cannot be used during the backup process since it is“offline” for users. Moreover, users may be unable to access the filesduring a full system backup. Accordingly, the cost of performing suchbackups is greater in terms of user productivity and/or systemresources.

FIG. 1 illustrates such an offline backup. At a point in time t₁ anapplication system DB will be shutdown or set offline. Now for a periodof time t_(b1) the movement of actual data objects takes place from theapplication system DB to a backup storage TSM as indicated by referencenumber 1. After completion of this backup process the application systemDB will be set online or start up again at a point in time t₂. Fromthere on logs of the application activity, so-called redologs 2 will bewritten by the application system DB and saved to the backup storagesystem TSM until the next backup process starts or the application goesoffline at a point in time t₃.

Another type of backup can be referred to as an “online” backup which isillustrated in FIG. 2. In an online backup, an application system DBthat is being backed up is placed in a different mode at a point in timet₁, called “online backup mode”, and stays in this mode during thebackup process, namely within a period of time t_(b11). The mechanics ofthis online backup mode or hot backup mode is proprietary to a specificapplication. The similarity for all application systems which areregarded within the scope of the present invention is the creation ofmore detailed log information describing application activity relevantto the data repository to enable later restoration of this repositoryduring recovery. This additional log information is made persistentwithin the redologs of the application system. Typically, a backupprocess performed during the period of time t_(b11) performs a fullsystem backup every time the files are backed up as indicated byreference number 1. A full system backup ensures that a complete andconsistent set of data objects on the application system DB is copied toa secondary or redundant storage, namely a backup storage system TSM. Incase of an online backup all redologs produced during the online backupmode t_(b11), need to be saved by the backup storage system TSM asindicated by reference number 2. After completion of this backup processthe application system DB will be set in normal operation mode at apoint in time t₂. Since there may be open transactions within theapplication system DB at the end of the backup process at point in timet₂ the latest redologs 3 need to be saved in addition in a time periodt_(b12) when all transactions are closed which where open duringt_(b11). This means a complete consistent set of application data existswithin the backup repository not before the point in time t₃ when this“delayed” redologs are saved. That means that a complete backup takes aperiod in time t_(b1) corresponding to the sum t_(b11)+t_(b12). Anindicated period in time t_(b2) shows that afterwards logs of theapplication activity, so-called redologs 4 will be written by theapplication system DB and saved to the backup storage system TSM untilthe next backup process starts or the application system DB goes offlineat a point in time t₄.

A backup process can be established to backup data on a regular orperiodic basis (e.g., daily, nightly, weekly, etc.).

However, as present business applications run virtually around the clockwith little tolerance for any downtime, the time frame or window forbacking up data is small if it exists. Recovering data often requiresthe application of a database to restore and recover logs of data.Generally, a log file is a list of actions that have occurred for thepurpose of analysis at a later time, for diagnostic or measurementpurposes. It is possible to maintain a temporary log of datatransactions since the last save of data. When a user saves data to thedatabase, the temporary log is wiped out. Normally, log files onlycontain forward information, thereby limiting the use and effectivenessof the log files in restoring information. Within the context ofrestoring and within the following description log files will bereferred to as redologs. By definition, restoration is to a point in thepast. The fact that redologs can only move information forward throughtime implies that they must be used in conjunction with some other formsof data restoration, such as restoring an offline full backup, in orderto achieve a restoration to a point in the past. Restoration proceeds byoverwriting the data with stored copies and by undoing the changes tothe redologs. According to such a procedure it is very difficult topreview a specific time frame or window in which a recovery can be done.

Restoring of data corresponds to replace data of the so-calledproduction computer with data of the backup stored on a backup storagesystem. Therefore, it is very important, that the backup is preciselydone, because otherwise wrong data are brought in during restoring. Inthe worst case, the database is unusable after termination of therestoring.

There are different possibilities to proceed a backup.

A user executes a regular backup under optimised use of his resources.The backup of a database for example is executed according to thefollowing steps. The data of the database are first copied. With respectto the used procedure, changes are saved during or after the backup.

If recovery is decided, the point in time at which the recovery has tobe executed has to be determined. All data which have been deposited inthe database until this point in time have to be restored. Afterrestoring, the so-called recovery can be started, so that the completefunctionality of the database is re-established.

The recovery time frame cannot be exactly estimated. Providers of arecovery service have no possibility to maintain predefined recoverytimes, because prediction of the time frame is hardly possible. Withinthe scope of the present invention the term “recovery time” covers thewhole period of time necessary to restore backed up data andcorresponding redologs as well as to recover those restored data withthe associated redologs.

SUMMARY

According to the present invention, a method for calculating a recoverytime of an application system in a computer system is provided fortuning the computer system dynamically, wherein the recovery time iscalculated and controlled within flexible predefined time slices andcompared to a predefined time period and a trigger is set in case thatthe calculated recovery time exceeds the predefined time period.

As already mentioned, the term “application system” covers, within thescope of the present invention, each kind of data storage, such as forexample databases and applications and log files thereof.

In a possible embodiment of the method the calculated recovery time isisochronously displayed for review.

In another possible embodiment of the method according to the presentinvention the trigger initiates a warning signal for a user.

Furthermore, it is possible that the trigger enables simulator optionson a corresponding client for modulating systematically backupperformance parameters. With help of a simulation of a specific scenarioa recovery time can be determined or at least estimated. This can beused again to modulate backup performance parameters accordingly. Such asimulation can also lead for example to an activation of additionalappropriate system resources for reducing the recovery time.

In still another possible embodiment of the method according to thepresent invention the trigger initiates a warning signal combined withan activation of additional appropriate system resources for reducingthe recovery time. It is possible that a simulation is performed firstafter the warning signal, leading then to an activation of additionalappropriate system resources for reducing the recovery time.

In a further embodiment of the method, an execution plan for a backup isgenerated on the basis of the calculation of the recovery time. Theexecution plan comprises a schedule of the execution of the backup andthe backup is executed on demand according to the execution planschedule.

It is possible, that the recovery time is determined using the followingsystem parameters: backup duration of saved data of the applicationsystem, an amount of associated redologs of the application system,throughput values for a backup of the redologs and an overall throughputfor a recovery of the saved data with the associated redologs.

With help of these parameters the recovery time can always be calculatedand compared with the predefined time period. If the calculated recoverytime achieves the predefined time period, a provider can be informedand/or further backup- or restore-resources can be provided so that thepredefined time period can be met.

There are different possibilities for implementing the method. There isa possibility only to give a warning signal to a corresponding provider.Furthermore, a warning signal can be combined with various options foroptimising the backup. An automatic schedule of the backup withprovision of appropriate backup- or restore-resources can also beprovided. Another possibility is to execute in preliminary stages asimulation with respect to the environment of a specific user combinedwith the calculation of the recovery time frame together with the neededbackup and restore resources.

The method, as described above, can be implemented whenever users havecertain needs on how long their business can afford to stay offline witha certain application. Whenever questions like “how fast must anapplication be recovered” or “how much time is allowed until restore andrecover is done” arise, the method can be applied.

According to an embodiment of the proposed method, parameters describingthe state of the computer system are continuously collected and used tocalculate the time, a full recovering of the data requested by aspecific critical application system will take. Such a calculated valuewill either be displayed for review or also may be used as an input fora schedule mechanism. Thus, a user can define how long a specificbusiness process allows him to be offline with a particular application.He may decide to schedule a new backup on demand if the predefined timeperiod is exceeded.

The present invention further refers to a computing system forcalculating a recovery time of an application system in a computersystem for tuning the computer system dynamically, the system comprisinga calculating unit for calculating the recovery time within flexiblepredefined time slices, a control unit for comparing the calculatedrecovery time with a predefined time period and an indicator unit forindicating when the calculated recovery time exceeds the predefined timeperiod.

In a possible embodiment of the computing system according to thepresent invention, the system further comprises a monitor unit with thehelp of which the calculated recovery time can be isochronouslydisplayed for review.

In still another embodiment of the computing system, the system furthercomprises a generating unit for generating an execution plan for abackup on the basis of the calculation of the recovery time, theexecution plan comprising a schedule of the execution of the backupaccording to which the backup can be executed.

It is possible that the computing system determines the recovery timeusing the following system parameters: backup duration of saved data ofthe application system, an amount of associated redologs of theapplication system, throughput values for a backup of the redologs andan overall throughput for a recovery of the saved data with theassociated redologs.

Furthermore, the invention covers a computer program product in acomputer-readable storage medium for carrying out a method when thecomputer program is run on a computer. In one illustrative embodiment,the computer-readable storage medium is a tangible computer-readablestorage medium, such as a memory, hard drive, floppy disk, CD-ROM,DVD-ROM, or the like.

Further features and embodiments of the invention will become apparentfrom the description and accompanying drawings.

It will be understood that the features mentioned above and thosedescribed hereinafter can be used not only in the combinations specifiedbut also in other combinations or on their own, without departing fromthe scope of the present invention.

For purposes of clarity, the present discussion refers to networkdevices and concepts and terms of specific examples.

However, the method and the computing system of the present inventionmay operate with a wide variety of types of network devices includingnetworks and communication systems dramatically different from specificexamples illustrated in the following drawings. It should be understoodthat while the invention is described in terms of a computer system,that the invention has applications in a variety of communicationsystems, such as advanced cable-television systems, advanced telephonenetworks or any other communication system that would benefit from thecomputing system or method according to the present invention. It isintended that the word “computer system” as used in the specificationand claims be read to cover any communication system unless the contextrequires otherwise.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention is schematically illustrated in the drawings by way ofexample and is hereinafter explained in detail with reference to thefollowing drawings:

FIG. 1 shows a schematic diagram showing a time lapse of an offlinebackup according to the prior art;

FIG. 2 shows a schematic diagram showing a time lapse of an onlinebackup according to the prior art;

FIG. 3 shows a schematic diagram showing a time lapse of an onlinebackup and a succeeding recovery according to an embodiment of themethod according to the present invention;

FIG. 4 shows a system diagram showing an embodiment of a computer systemaccording to the present invention;

FIG. 5 shows a flowchart of another embodiment of the method accordingto the present invention;

FIG. 6 shows a possible implementation of the method according to thepresent invention;

FIG. 7 shows another possible implementation of the method according tothe present invention;

FIG. 8 shows a further possible implementation of the method accordingto the present invention.

DETAILED DESCRIPTION

FIGS. 1 and 2 have already been described before in connection with thesummary of the related art.

FIG. 3 shows an application system DB and a backup storage system TSM.The backup storage system TSM can be for example a so-called TivoliStorage Manager, a product of IBM®. As part of the IBM TotalStorage®Open Software Family, IBM Tivoli Storage Manager empowers an user with aflexible backup method for his computer system. The Tivoli StorageManager is mainly adapted to specific operating systems, as for exampleto a so-called AIX system. The operating system AIX is a so-called filesystem which expands over a so-called logical volume. The Tivoli StorageManager helps to protect data and to provide bare metal restorecapabilities. It offers a comprehensive system backup, restore andreinstallation tool.

The application system DB and the backup storage system TSM are linkedwith each other over a time bar. The backup storage system TSM managesbackups of data files 1 and redologs 2, 3 and 4 of the applicationsystem DB. Furthermore, the backup storage system TSM keeps records ofthe amount of data of both types, namely of backups of data files 1 ofthe application system DB and archives of redologs of the applicationsystem DB. In case of an online backup all redologs produced during theonline backup mode t_(b11), need to be saved by the backup storagesystem TSM as indicated by reference number 2. After completion of thisbackup process the application system DB will be set in normal operationmode at a point in time t₂. Since there may be open transactions withinthe application system DB at the end of the backup process at point intime t₂ the latest redologs 3 need to be saved in addition in a timeperiod t_(b12) when all transactions are closed which where open duringt_(b11). This means a complete consistent set of application data existswithin the backup repository not before the point in time t₃ when this“de-layed” redologs are saved. That means that a complete backup takes aperiod in time t_(b1) corresponding to the sum t_(b11)+t_(b12). Anindicated period in time t_(b2) shows that afterwards logs of theapplication activity, so-called redologs 4 will be written by theapplication system DB and saved to the backup storage system TSM untilthe next backup process starts or the application system DB goes offlineat a point in time t₄. The time bar shows a point in time t_(A) where arestore/recovery process starts. A further point in time marked as “0”specifies the point in time until to which data should be restored andrecovered in order to rebuild the state of the application system DB atthis point in time. Changes within the data which happened during “0”and t_(A) are lost.

Backups are copies of active online data stored on offline storage.Should an online storage device fail, a data error occur or someoneaccidentally deletes a file, the offline copy of that data can becopied, namely restored, to online storage. The already mentioned TivoliStorage Manager TSM uses multiple techniques to make data backups andrestores as fast, flexible and low-impact as possible.

Knowing the amount of data of both types and the time it consumes toexecute the backups of data files 1 and archives of redologs 2 and 3 ofthe application system DB and the knowledge about the internalperformance of the system, the time it will consume to restore the datafrom the backup can be calculated. The time it will consume to restorethis data from the backup and the corresponding redologs will correspondto t_(r1) and t_(r2) as it is indicated in FIG. 3. It is also known howmany redologs have been archived since any specific backup up to thepoint in time 0. This can be designated as “Size_log_backup”.Furthermore, it is known how fast the system can recover its ownredologs, called “recovery_speed”. This value needs to be made availableto a certain backup application for instance by typing it for exampleinto a dialog. If the backup application knows about the“Size_log_backup” and the “recovery_speed”, it can calculate the plainrecovery time, called t_(r3). The plain recovery time t_(r3) resultsfrom the following equation:

$t_{r\; 3} = \frac{{Size\_ log}{\_ backup}}{recovery\_ speed}$

The “Size_log_backup” is dependent on a certain point in time anadministrator chooses to recover the backup. The more early this pointis in time the more will the “Size_log_backup” decrease. The recoverytime t_(r3) is direct proportional to the “Size_log_backup”. Now havingall values t_(r1), t_(r2), t_(r3), the overall recovery time t_(r) willcalculate as following:t _(r) =t _(r1) +t _(r2) +t _(r3).

The calculated value t_(r) will now either be displayed for review ormay directly serve as an input for a schedule mechanism. A user candefine how long his business process allows him to be offline with aparticular application and may decide to schedule a new backup on demandif a predefined time period is exceeded by the calculated value t_(r).

FIG. 4 shows an example of a computing system according to the presentinvention, more particularly a backup environment based on existingapplications used to protect a so-called SAP R/3 database 10.Backup/restore processing of the database 10 is done by a databasespecific unit 20, called Data Mover and a further specific unit 30,called Storage Manager. FIG. 4 also shows a so-called AdministrationAssistant 40 providing system administrators with means to administerthe backup/restore processing. The Administration Assistant 40 isimplemented as a client/server application. The Administration Assistant40 comprises a server 41. The server 41 stores performance data receivedfrom the Data Mover 20. On its' browser based client it provides theuser with several monitor panels like a performance monitor or a systemStatus Monitor 42.

For every backup and archive process the process duration and the amountof data saved and the amount of redologs archived are transferred to theAdministration Assistant server 41 and stored in its' history. Acalculating unit 43, called Recovery Calculator 43 is provided which hasto be initialised by a user by means of an Administration AssistantClient 50 specifying a system's recovery speed, a time intervalindicating up to which point of time after the last backup the systemhas to be recoverable and a predefined time period t₀ corresponding to amaximum time frame for a recovery process. This is done over aconnection 1 a. The Recovery Calculator 43 uses this data and theduration and data amount values from the Data Store 41 (connection 1) tocalculate an overall recovery time t_(r). It then compares the overallrecovery time t_(r) with the predefined maximum recovery time t₀.Depending on the result of this comparison appropriate actions aretaken. There are three different ways the result can be handled:

-   -   The result will be sent over a connection 2 a to the Status        Monitor 42. Within this monitor 42 a new column “recovery        status” will be updated. The corresponding monitor panel can be        viewed with the Administration Assistant Client 50 over a        connection 3 a.    -   If the overall recovery time t_(r) exceeds the maximum recovery        time t₀ an existing scheduler application 60, e.g. a Tivoli        Workload Scheduler, may be called to schedule/start a new        backup, indicated by a connection 3 b.    -   Alternatively the user may want to try to optimise the restore        process by calling a simulator module 44, called Restore        Simulator. The simulator 44 will automatically vary all        performance relevant configuration parameters of the application        system to find the minimum restore duration and will suggest an        optimised configuration parameter set which the user can then        decide to apply. This is indicated by a connection 3 c.

FIG. 5 shows a flowchart representing a recovery time calculation foronline backups of an application system according to a possibleembodiment of the method according to the present invention. Acalculating unit of an appropriate computing system which does thecalculation holds a set of default values:

-   -   a predefined time period, namely a target restore interval T₀        which will be used as a reference and should not be exceeded,    -   recovery speed values v_(rec1) and v_(rec2) for different        redolog types. There are generally two types of redologs, namely        those which are performed during a backup, represented by a1,        and those which are performed after a backup, signed as a2.    -   a correction factor f_(r1) which has to be used to calculate the        restore time of the saved data files.

All these values can be adapted by a user at any time. After a data filebackup has been finished the calculating unit stores the correspondingbackup duration t_(b1). This value can be used to calculate the timet_(r1) necessary to restore this data. According to experience therestore lasts a little longer than the corresponding backup. Therelation between t_(b1) and t_(r1) can be expressed as following:t _(r1) =t _(b1) +f _(r) *t _(b1)

Accordingly the restore time for the redologs is a little longer thanthe corresponding archive:t _(r2) =t _(b2) +f _(r) *t _(b2)

The correction factor f_(r) has been found by experience(˜0.15).

Archiving of redologs may already start while the data file backup isbeing processed. As already mentioned, there is a difference betweenarchives being processed during a backup and those being processed afterthe backup has been finished. Redologs that are written during a backupcontain much more data for a comparable content than those written afterthe backup has been finished. As the recovery time is not proportionalto the amount of data but to the content to be restored, the recoveryspeed for the former redologs (created during the backup) v_(rec1) is alittle higher than V_(rec2). This leads to different recovery speedvalues V_(rec1) and V_(rec2) for both archive types. For every finishedarchive the calculator adds the duration t_(a) to the total restore timet_(r2) and depending on the archive type (performed during a backup: a₁or after a backup: a₂) the amount of data saved is added to S_(a1) orS_(a2). The recovery time t_(r3) for all redologs can be calculated withthe following expression:t _(r3) =S _(a1) /v _(rec1) +S _(a2) /V _(rec2)

The total recovery duration t_(r) can be calculated with:t _(r) =t _(r1) +t _(r2) +t _(r3)

The result t_(r) is finally checked against the predefined time periodt₀. If t₀ is exceeded the appropriate application is informed.

It has to be noted that the calculation for offline backups can be donewith the same algorism. In this case only archives after a finishedbackup are processed.

FIG. 6 shows a possible implementation of the method according to thepresent invention where only visual (and accustic) warnings arepresented to a user. An existing monitor application which provides aset of status information can be enhanced to show an additional valuefor a recovery interval, namely a recovery time t_(r). Depending on thetime limit exceedance the recovery interval status may be displayed as ared or green indicator on a corresponding client GUI (graphical userinterface).

FIG. 7 shows another possible implementation variant of the methodaccording to the present invention where visual (and accustic) warningsare combined with additional features for backup optimization. Anexisting monitor application which provides a set of status informationcan be enhanced to show an additional value for a recovery interval,namely a recovery time t_(r).

It is possible to implement a kind of assistant during arestore/recovery process. As already stated, the recovery time t_(r3)and thus the overall recovery time t_(r) is dependent on the point intime “0” recover to. Having this knowledge, the implemented assistantcan support an administrator for a recovery by proposing a point in timethat can be recovered within the predefined time period, namely amaximum recovery window. Also there might be parameters available totweak the restore time where the assistant can also either propose orautomatically change values to meet the maximum recovery window with anefficient use of available resources as for example tape drives, networkconnections, priority for copy processes etc. These are parameters whichare available to tweaken the restore times.

Depending on the time limit exceedance the recovery interval status maybe displayed as a red or green indicator on a corresponding client GUI.In case of a red indicator a user will be able to start a simulationprocess. Two different enhancement procedures are conceivable.

It is possible to perform a parameter optimization. In this case asimulator automatically checks all possible parameter combinations anddetermines the optimum performance parameters. The result is presentedto the user who then can decide to accept the new settings. An update ofthe configuration profiles may be automatically done by the applicationsystem or manually by the user.

Furthermore, it is possible to perform a backup schedule optimization.In this case a scheduler tries to increase the number of backups toreduce the total recovery time. The new schedule is presented to theuser who then can decide to accept the new settings.

FIG. 8 shows still another implementation variant of the methodaccording to the present invention where an automatic re-schedulingmechanism starts in case a predefined time period t₀ has been exceededby a calculated recovery time t_(r). A scheduler tries to increase thenumber of backups to reduce the total recovery time t_(r).

1. A method, in a data processing system, for calculating a recoverytime of an application system in a computer system for tuning thecomputer system dynamically, the method comprising: determining, by arecovery calculator of the data processing system, a type of redologused during a backup process and a corresponding recovery speed valueassociated with the type of redolog, wherein the type of redolog is oneof a plurality of different types of redologs, and wherein the recoveryspeed value associated with the type of redolog is different fromrecovery speed values of other types of redologs in the plurality oftypes of redologs; calculating, by the recovery calculator, the recoverytime based on the type of redolog used during the backup process and thecorresponding recovery speed value associated with the type of redolog;comparing, by the recovery calculator, the calculated recovery time to apredefined maximum recovery time period; and setting a trigger, in astatus monitor of the data processing system, for performing anoperation in response to the calculated recovery time exceeding thepredefined maximum recovery time period.
 2. The method according toclaim 1, wherein the calculated recovery time is isochronously displayedfor review.
 3. The method according to claim 1, wherein, the triggerinitiates a warning signal for a user.
 4. The method according to claim1, wherein the trigger initiates a warning signal combined with anactivation of additional appropriate system resources for reducing therecovery time.
 5. The method according to claim 1, wherein the triggerenables simulator options on a corresponding client for modulatingsystematically backup performance parameters.
 6. The method according toclaim 1, wherein an execution plan for a subsequent backup process isgenerated on the basis of the calculation of the recovery time, theexecution plan comprising a schedule of the execution of the subsequentbackup process and the subsequent backup process being executed ondemand according to the execution plan schedule.
 7. The method accordingto claim 1, wherein the recovery time is determined using the followingsystem parameters: backup duration of saved data of the applicationsystem, an amount of associated redologs of the application system,throughput values for a backup of the redologs, and an overallthroughput for a recovery of the saved data with the associatedredologs.
 8. A data processing system, comprising: a recovery calculatorunit in the data processing system; and a status monitor unit, in thedata processing system, coupled to the recovery calculator unit, whereinthe recovery calculator unit: determines a type of redolog used during abackup process and a corresponding recovery speed value associated withthe type of redolog, wherein the type of redolog is one of a pluralityof different types of redologs, and wherein the recovery speed valueassociated with the type of redolog is different from recovery speedvalues of other types of redologs in the plurality of types of redologs,calculates a recovery time based on the type of redolog used during thebackup process and the corresponding recovery speed value associatedwith the type of redolog, compares the calculated recovery time to apredefined maximum recovery time period, and sets a trigger, in thestatus monitory unit, for performing an operation in response to thecalculated recovery time exceeding the predefined maximum recovery timeperiod.
 9. The computing system according to claim 8, wherein the statusmonitor unit outputs the calculated recovery time to be isochronouslydisplayed for review.
 10. The computing system according to claim 8,further comprising a generating unit for generating an execution planfor a subsequent backup process on the basis of the calculation of therecovery time, the execution plan comprising a schedule of the executionof the subsequent backup according to which the subsequent backup can beexecuted.
 11. The computing system according to claim 8, wherein therecovery time is determined using the following system parameters:backup duration of saved data of the application system, an amount ofassociated redologs of the application system, throughput values for abackup of the redologs and an overall throughput for a recovery of thesaved data with the associated redologs.
 12. A computer program productin a computer-readable storage medium for carrying out a method when thecomputer program is run on a computer, the method comprising:determining a type of redolog used during a backup process and acorresponding recovery speed value associated with the type of redolog,wherein the type of redolog is one of a plurality of different types ofredologs, and wherein the recovery speed value associated with the typeof redolog is different from recovery speed values of other types ofredologs in the plurality of types of redologs; calculating a recoverytime of an application system in a computer system based on the type ofredolog used during the backup process and the corresponding recoveryspeed value associated with the type of redolog; comparing thecalculated recovery time to a predefined maximum recovery time period;and setting a trigger for performing an operation in response to thecalculated recovery time exceeding the predefined maximum recovery timeperiod.
 13. The method of claim 1, wherein calculating the recovery timefurther comprises: calculating a backup duration for the backup processafter completion of the backup process; and calculating the recoverytime based on the backup duration and a correction factor, wherein thecorrection factor represents an adjustment of the backup durationindicative of an amount of time in excess of the backup durationrequired to perform a restore operation based on the data stored by thebackup process.
 14. The method of claim 1, wherein calculating therecovery time further comprises: calculating the recovery time based ona combination of a first value and a second value, wherein the firstvalue is calculated as an amount of data saved during the backup processusing a first redolog type, divided by a recovery speed valuecorresponding to the first redolog type, and wherein the second value iscalculated as an amount of data saved during the backup process using asecond redolog type, different from the first redolog type, divided by arecovery speed value corresponding to the second redolog type.
 15. Themethod of claim 1, wherein the plurality of types of redologs comprisesa first type of redolog in which the redolog is generated during thebackup process, and a second type of redolog in which the redolog isgenerated after the backup process is completed.
 16. The method of claim1, wherein the trigger initiates a simulator that varies performancerelated configuration parameters of an application system of the dataprocessing system to determine a minimum restore duration and providesan output to a user indicating configuration parameters corresponding tothe minimum restore duration.
 17. The computer program product of claim12, wherein calculating the recovery time further comprises: calculatinga backup duration for the backup process after completion of the backupprocess; and calculating the recovery time based on the backup durationand a correction factor, wherein the correction factor represents anadjustment of the backup duration indicative of an amount of time inexcess of the backup duration required to perform a restore operationbased on the data stored by the backup process.
 18. The computer programproduct of claim 12, wherein calculating the recovery time furthercomprises: calculating the recovery time based on a combination of afirst value and a second value, wherein the first value is calculated asan amount of data saved during the backup process using a first redologtype, divided by a recovery speed value corresponding to the firstredolog type, and wherein the second value is calculated as an amount ofdata saved during the backup process using a second redolog type,different from the first redolog type, divided by a recovery speed valuecorresponding to the second redolog type.
 19. The computer programproduct of claim 12, wherein the plurality of types of redologscomprises a first type of redolog in which the redolog is generatedduring the backup process, and a second type of redolog in which theredolog is generated after the backup process is completed.
 20. Thecomputer program product of claim 12, wherein the trigger initiates asimulator that varies performance related configuration parameters of anapplication system of the data processing system to determine a minimumrestore duration and provides an output to a user indicatingconfiguration parameters corresponding to the minimum restore duration.